For examinations, especially in fields of orthopedics and neuro-orthopedics which deal with functional disorders of the motor system, it is important to determine by measurement and to evaluate diagnostically certain positions and movements of body parts. For example, conclusions as to the function of the cervical portion of the spine and the upper dorsal column are possible through registration of the position and motion of the head. Functional disorders of these spinal regions are the most common cause for aches of the upper torso, arms and head. Even though static analyses can be carried out with present-day examination procedures (X-ray, scanning, etc.), an examination of the dynamics and function of the spine is only very limitedly realizable. Both the technique of this procedure and the radiation exposure set narrow limits for functional tests of the spine. A three-dimensional recording of the position of the head is possible with optical checking processes (film, video), but only with utilization of complex machinery and for specific functions.
For measuring head movements, there has already been made known (U.S. Pat. Nos. 3,161,846 and 3,290,935) a device of the kind initially set forth which, however, is not suited for diagnostic purposes since the free mobility of the head is excessively restricted so that diagnostically significant final positions of the head movements and rapid movements are not detectable. Furthermore, the known device does not give the physician access to the head to the extent necessary for diagnostic purposes.